<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>
    p {
      width: 800px;
      font-size: 30px;
    }
  </style>
</head>

<body>
  <p>css是给html添加了样式，就是给html穿了衣服</p>
  <div style="width:200px;height:400px;background-color:pink;">这是一个div</div>
</body>

</html>